People may engage in anilingus for its own sake, before anal fingering or penetration, or as part of foreplay. Comic books often featured characters being tied up and tying others up, particularly in damsel in distress plots. Entacle erotica describes a type of pornography most commonly found in Japan which integrates traditional pornography with elements of bestiality and a fantasy, horror, or science-fiction theme. Diaper pornography involves performers wearing diapers, sometimes with an adult performer acting in the role of a caretaker. Animal masturbation has been observed in many species, lesbian hentai both in the wild and in captivity. A few extremely flexible males can reach and stimulate their penis with their tongue or lips, and so perform autofellatio. Sigmund Freud considered foot binding as a form of fetishism. Lolita pornography features women who are 18 years old or slightly older, who pretend to be underage teen girls. Advocates of RACK argue that SSC can hamper discussion of risk because no activity is truly safe, and that discussion of even low-risk possibilities is necessary for truly informed consent. Men may find stimulation of the anus, rectum, big tit milf and adjacent organs enjoyable. The term Asiaphile is sometimes used to young gay porn describe the same phenomenon as is yellow fever . It is typically animated pornography, as the legal age to be featured in a pornographic film in Japan is 18. Sexual orientation Pornography features an increasing variety of combinations of actors by their sexual orientation such as lesbian, gay, bisexual, and transsexuals in addition to traditional heterosexual roles. Types of anal sex can also be a part of lesbian sexual practices. Its primary goal is sexual arousal in its audience. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Examples of heterosexual pornographic film series featuring creampies include Cream Filled Teens and Internal Cumbustion. Transgender pornography features performers who cross-dress for sexual gratification, either for themselves or for their partners.